We report on the molecular beam epitaxial growth and characterization of In(Ga)N nanowires on Si(111)
substrates. We also describe the growth and optical properties of InGaN/GaN dot-in-a-wire heterostructures on Si(111)
substrates with emission in the green, yellow, and red wavelength range. The design, fabrication, and characterization of
In(Ga)N nanowire solar cells and LEDs are discussed. InN p-i-n axial nanowire homojunction solar cells exhibit a
promising short-circuit current density of ~ 14.4 mA/cm2 and an energy conversion efficiency of ~ 0.68% under 1-sun,
AM1.5G illumination. Strong green, yellow, and amber emission has also been achieved from InGaN/GaN dot-in-a-wire
LEDs at room temperature.

Photoluminescence (PL) and absorption measurements have been made on CdSe1-xSx nanoparticles with x=0.69 to x=1
using a process that should lead a graded sulfur fraction where the sulfur fraction is lowest in the core. There is a
systematic increase in the 1S3/2→1Se transition energy and the 1Se→1S3/2 PL emission energy that can be attributed to an
increasing sulfur concentration. The quantum yield is ~30% for 0.69≤x≤0.83. It decreases to 0.7% for higher values as x
approaches 1. The higher quantum yields for x≤0.83 may be due to the graded sulfur concentration that leads to a
thermal barrier that reduces non-radiative recombination at the surface. Temperature dependent PL measurements on a
x=0.83 sample are consistent with two PL lifetimes where the longer one (~30 ns) is nearly temperature independent and
could arise from a fraction of the nanoparticles having a lower concentration of non-radiative recombination sites. The
shorter component can be accounted for by thermal activation to surface non-radiative recombination sites with an
activation energy of 9.6 meV.

Photodiode (PD) is a key component in optical transmission and optical measurement systems. In this paper, we present
the design and fabrication of traveling-wave edge-coupled Unitraveling Carrier (UTC) PD. The fabricated UTC PD with
40μm×5μm waveguide shows 3dB bandwidth 13GHZ and 32GHz under 0 biases and -1V respectively. In parallel, PIN
PD was also fabricated for comparison and only shows 4GHz and 18GHz under same bias conditions. This indicates the
UTC PD is superior to the PIN PD for higher speed operation, especially in application of system without power supply.

Nitrogen status is an important factor for evaluating the growth of rice or the amount of nitrogen fertilizers needed per
rice field. It can be done easily and cheaply by using a leaf color chart. However, the accuracy of the resulting color level
depends on the ability of the farmer to compare the leaf color with the reference chart as well as on the direction of Sun
light. With this issue in mind, this paper proposes a low-cost light-emitting-diode (LED) based leaf color meter that can
be used to estimate the nitrogen level needed in the rice field. In particular, we show how we integrate an off-the-shelf
green 562-nm wavelength LED, a silicon photodiode, an 8-bit microcontroller, and a 6×1 LED panel in a compact
packaging style for the implementation of this needed leaf color analyzer. The total cost is only USD39. Field test results
confirm that key leaf color levels of 2, 3, and 4 can be identified. Other key features are ease of use and upgradability for
different color levels.

In order to study the performance of MRPC, which will be used for the upgrade of the Endcap TOF in
BES III, a T0 system is composed of high speed response PMTs H6533 coupling with BC420 plastic
scintillators. Because the T0 system should offer a toughly strict timing start, the high precision
electronics based on VME system were used to test the SPS (single-photoelectron spectrum) of H6533
PMT. A suitable operation voltage for optimal performance is confirmed by researching the
dependence relationship between the PMT gain and energy resolution of SPS (single-photoelectron
spectrum). At the end, the timing resolution of this type of T0 system was 41.6 ps in the cosmic ray test
and 39.1 ps in the proto beam test.

Investigating the effects of solvents on the performance of poly(3-hexylthiophene-2,5-diy1) (P3HT):C61-butyric acid
methyl ester (PCBM) bulk heterojunction solar cells, we found the short current density (Jsc), fill factor(FF),and power
conversion efficiency (η) of a cell with a photo-active layer made using materials dissolved in a higher boiling point
solvent to be higher than those of a cell made using the same materials dissolved in a low boiling point solvent.
Evaluating the surface morphology, charge mobility, and current-voltage curve of cells made using different solvents, we
concluded that the polymer films using a higher boiling point solvent had longtime to self-organize, got a higher degree
of crystalline, led to lower device series resistance, thereby increased the short current density (Jsc), fill factor(FF),and
power conversion efficiency (η) of the photovoltaic devices.

Image restoration for constructing high-spatial-resolution images in an imaging system which realizes indirectly far-filed
imaging by integrating the microlenses array with LCD is reported. We have investigated the indirectly far-field imaging
condition where adjacent sampling points contribute the detected signal. Experimental setup with microlens of 500 μm
diameter and 8 mm focal length is built to prove this condition by studying performance of image restoration using
modified point spread function (PSF). Since any one iterative method is not optimal for all image deblurring problems,
some deblurring algorithms including direct deconvolution and iterative deconvolution are applied to our imaging system
and we compared the effectiveness of these iterative procedures to choose right one for our use.

Towards the development of high efficient GaN-based Vertical Cavity devices, the fabrication of cracks-free
high reflective semiconductor mirrors is still an issue. For near-UV operating devices, one of the best solution is
the use of AlGaN/GaN materials family. With a relatively high Al molar fraction in AlGaN, a large enough
index contrast can be achieved to fabricate high reflectivity mirrors. However, the lattice mismatch between
AlGaN and GaN increases with the Al molar fraction and induces a lot of cracks in the structure which affect its
optical and electrical properties. Moreover, for a regrowth of an active layer on the top of the mirror, it is
necessary to suppress crack generations to achieve a smooth surface. In this work, asymmetrical designs were
investigated for the modeling of fully-strained AlGaN/GaN distributed Bragg Reflectors with crack-free
surfaces. First, the critical thickness of MOVPE-grown AlGaN on GaN-on-sapphire templates was
experimentally determined and modeled. Then, several AlGaN/GaN mirrors with various Al molar fractions and
asymmetry factors were simulated demonstrating that non relaxed DBRs could be obtained with adequate
parameters. Finally, it has also been shown that there is a best suited Al molar fraction in AlGaN for each DBR
centering wavelength.

Light beam propagation at a prism-magnetic fluid film interface is experimentally studied. The magnetic fluid is made
through dispersion of synthesized cigar-shaped sub-micron particles of Fe2O3 in an oil solution. This was injected into a
glass cell with an active area of 10mm2 and a depth ranging from 10 microns to 30 microns whose base is a glass
microscope slide and on the top it was covered with a glass prism. The set up was developed by one of the authors to
measure light switching at a prism-liquid crystal interface in a previous publication.1 Polarized Light (TE or TM) from a
He-Ne laser impinges at the prism-magnetic film interface. The external reflected light is detected by a photodiode
connected to a data acquisition system. Since the properties of the magnetic fluid can be modulated by external magnetic
fields, we investigated the effects of the magnetic field on the refractive index of the magnetic fluid.
For our magnetic fluid, the reflection of light has been investigated as a function of particles concentration and thickness
of the films with a wavelength of 633nm and both TE and TM polarization, and applied magnetic fields up to 25 Oe. It
was found that the intensity of reflected light increases with increasing magnetic field up to 4 times the initial value, and
saturates at 20 Oe for TE light, while decreases with increasing magnetic field up to 4 times less for TM light with the
same saturation value. Moreover, under a given magnetic field, the output light increases with the increasing film
thickness in TE polarization, and decreases with the increasing film thickness in TM case. The refractive index of the
magnetic fluid depends on the concentration of the dilute oil-based magnetic fluid under zero field.
These behaviors are explained in terms of the organization of the submicron particles when the magnetic field is
applied.2 The cigar-shaped sub-micron particles are oriented along their long axis to form an organized mesostructure.
The different aggregation ability of the magnetic fluid particle is responsible for the variation of the optical properties
under different magnetic fields and for different polarization of the incident light.
It is noteworthly that the magnetically modulated refractive index of the magnetic fluid film could have great potential in
electro-optical applications. In particular, according to the experimental results, we believe that the fluid films that we
are proposing, thanks to the optical responses and the relative times, is a very good candidate to design Fiber Optical
Sensors (FOS) for magnetic fields.

SOI (silicon-on-insulator)-based micro-resonator is the key building block of silicon photonics, which is considered as a
promising solution to alleviate the bandwidth bottleneck of on-chip interconnects. Silicon-based sub-micron waveguide,
microring and microdisk devices are investigated in Institute of Semiconductors, Chinese Academy of Sciences. The
main progress in recent years is presented in this talk, such as high Q factor single mode microdisk filters, compact thirdorder
microring filters with the through/drop port extinctions to be ~ 30/40 dB, fast microring electro-optical switches
with the switch time of < 400 ps and crosstalk < -23 dB, and > 10 Gbit/s high speed microring modulators.

Silicon photonics can found applications in optical interconnects and optical signal processing. Recent years, silicon
photonics was developed rapidly. In this paper, we report our research work on silicon photonics. Based on the standard
CMOS foundry, we studied the silicon waveguides and related photonic components.

For the SOI-waveguide directional coupler (WDC), optical access loss (OAL) and polarization dependence (PD) are two
critical performance specifications which seriously affect the adoptability and deployment of a device, including optical
on-chip loss (OCL), polarization dependent loss (PDL) and extinction ratio of a 3dB-coupler based device. In this work,
using a commercial software tool - FIMMPROP, the performance of an SOI-WDC is simulated. Simulations find that the
curved waveguides for the turning sections of a 3dB WDC not only enlarge the footprint size, but also seriously
deteriorate the device performance. For instance, the two curved waveguide sections of a WDC induce an unpredictably
large change in the 3dB-coupling length, increase an OAL of 0.4-0.9dB, and seriously deteriorate the PD, and these
performance changes radically depend on rib size. After a corner-turning mirror (CTM) structure is introduced to a 3dB
SOI-WDC, the experiments show both the footprint length and 3dB-coupling length are unchanged, the OAL of the 3dB
coupler is only 0.5dB which is close to the simulation value. Therefore, for a 3dB-coupler based Mach-Zehnder
interference (MZI) structure, the OCL will be controlled to be <1.0dB in device design and will not depend on rib size.

The pump-to-Stokes RIN Transfer and its impact on output characteristic in silicon
Raman lasers are numerically investigated. The result shows that RIN transfer strongly influence
on the output RIN of the chip scale silicon Raman laser. High-frequency RIN transfer show
intense oscillation at about109Hz, which is several orders higher than that in Raman fiber laser
(about104Hz ). We also find that RIN transfer reaches a peak value at resonance frequencies and
decreases with the increasing the free carrier lifetime.

This paper illustrates the design and fabrication of wavelength filters using resonant cavity which is constructed out of a
phase shifted vertical side wall grating. The resonant cavity is analyzed as a Fabry-Perot resonator and the variation in
cavity quality factor (Q) and transmission with respect to various grating parameters is studied. It is observed that a high
Q-factor together with a high transmittivity can be obtained for this wavelength filter through optimization in grating
length and reduction in the out of plane loss. Multiple phase shifts are applied in the grating to get a coupled cavity
configuration so that channel isolation and spectral shape is improved. The channel wavelengths in a DWDM ITU grid
C band (100GHz spacing) is simulated by varying the phase shift length of the gratings and good channel isolation
with constant Q -factor and transmittivity is observed for the spectrum. The paper also explains the effective fabrication
process flow for this structure on a silicon wafer through e-beam lithography and Reactive Ion Etching (RIE).

In this paper, we calculate the thermal dissipation in semiconductor Optical Amplifier. We investigate
the effect of the material composition, the number of wells, the type of structure (Buried or Ridge), on the
thermal resistance of the component and try to extract some rules towards minimization of temperature
elevation. An increase in the number of quantum wells within the same type of structure increased the thermal
resistance but not significantly. The type of source, a concentrated single source or a distributed in the
different wells, does not play a significant role in the thermal resistance of a structure. The difference between
Pside up or down mounted device is clear and well known. The variation of Separate Confinement
Heterostructure has, in both the Pup and Pdown structures, almost no effect on the Rth. The influence of heat
repartition inside the wells has been evaluated. Finally the overall heat dissipation in the optical module is
calculated; the objective is to the decrease the overall electrical consumption keeping the performances
required by the application.

An Ytterbium-doped double-cladding fiber laser is demonstrated. The threshold of the pump power is about 1.1W. The
maximum output power is 9.9W at the wavelength of 1045nm when the pump power is 15.3W. The slope efficiency is
around 70%. We discuss an exact numerical model, with a shooting method to solve the power steady-state equations.
Numerical results about the output power as a function of the pump power are in good agreement with measurements.

Optical splitter is one of most typical device heavily demanded in implementation of Fiber To The Home (FTTH) system.
Due to its compatibility with optical fibers, low propagation loss, flexibility, and most distinguishingly, potentially costeffectiveness,
glass-based integrated optical splitters made by ion-exchange technology promise to be very attractive in
application of optical communication networks. Aiming at integrated optical splitters applied in optical communication
network, glass ion-exchange waveguide process is developed, which includes two steps: thermal salts ion-exchange and
field-assisted ion-diffusion. By this process, high performance optical splitters are fabricated in specially melted glass
substrate. Main performance parameters of these splitters, including maximum insertion loss (IL), polarization
dependence loss (PDL), and IL uniformity are all in accordance with corresponding specifications in generic
requirements for optic branching components (GR-1209-CORE). In this paper, glass based integrated optical splitters
manufacturing is demonstrated, after which, engineering-oriented research work results on glass-based optical splitter are
presented.

Multimode Interference (MMI) based devices are widely used due to excellent performance. Here in this paper, a 1×2
multimode power splitter based on MMI is designed using three-dimensional beam propagation method (3D-BPM), and
then fabricated in glass using the Ag+-Na+ ion-exchange technique. The width of the input and output multimode
waveguides was 50μm and they were tapered to 75μm at the interface to the MMI region. The MMI region was also
quadratically tapered .First, Ag+-Na+ ion exchange was run in nitrate melt at 350°C.Then an electric field was applied at
300°C so that the silver ions continued their migration award. Under the wavelength of 1550nm, the measured results
showed that the propagation loss of multimode straight waveguide can be lower than 0.31dB/cm, and the insertion loss
and uniformity of the splitter were 4.28dB and 0.21dB, respectively. Parameters of the fabrication process and structure
of the device can be optimized to improve the performance of the device.

In this work, we report a novel waveguide structure that hybridizes the conventional dielectric waveguides with novel
metal/dielectric plasmonic waveguides by incorporating the former inside the dielectric part of the latter. As a result, the
strongest field in the waveguide locates at the center of the guide instead of the metal/dielectric interfaces, which can
significantly reduce the propagation loss, and meanwhile offer excellent confinement of the plasmonic lightwave.
Theoretically the inside wave mode is to be shown a hybrid plasmonic-optical mode. We further analyze the mode
properties of such waveguides with various structure dimensions, and demonstrate its wave propagating characteristics
with numerical simulations. The theoretical study suggests that such waveguides are promising for ultra-compact
integration of lightwave circuit. Additionally, fabrication of such waveguides is compatible with current micro/nanofabrication
technologies.

Mach-Zehnder interference (MZI) construction is broadly exploited to implement optical switches and modulators in the field of integrated optical/photonic technology. Silicon-on-insulator (SOI) waveguides have been increasingly developed to implement highly integrated photonic devices and systems. In this work, for the SOI-waveguide MZI-type electro-optic (EO) modulated devices with free-carrier dispersion (FCD) effect, the FCD-induced extra optical absorption (EOA) loss and its negative impact upon the device performance are studied. An intrinsic limitation to this type of device is found to be the tension between the EOA loss and the interaction length for a half-wave modulation. The numerical calculation and professional software simulation show the EOA loss of <1.0dB determines an interaction length of 4-mm. The performance decay processes of both EO switch and modulator due to the modulation-induced EOA loss are modeled. The numerical calculation shows the optical on-chip (OC) loss is 1.0dB and the isolation between two outputs is 21dB for the EO switch, while for the EO modulator the OC loss is 1.0dB and 2.5dB at the off- and on-state, respectively, and the extinction ratio only approaches 20dB. The negative influence of this intrinsic limitation to the bandwidth of EO modulator is also analyzed.

Silicon-based electro-optic modulator is a key device that used to implement optical interconnections.
The paper is attempt to analyze the Silicon-on-insulator (SOI ) structure characteristics of resonator,
according to the transfer function. The spectra response of Single Micro-Ring (SMR) and Double
Micro-Ring resonators (DMR) with a ridge cross section on silicon was discussed emphatically. The
3dB bandwidth and the coupling coefficient affection on it were calculated and compared. The
relationship between the characteristics of resonators the coupling coefficient was analyzed. The
commercial software Rsoft was used to simulate the figures of SMR and DMR respectively. The
simulation results show that the 3dB bandwidth of DMR can be achieved much narrower than that of
SMR through the optimization design of the structural parameters. And the filter response line is
sheerer for the DMR.

Dichroic beam combiner is the kernel technology of the dual mode guiding simulation system. Based on the photonic
band gap structure of one-dimensional Photonic crystals, a new method of designing a diachronic beam combiner is
proposed in this paper, through which mid-IR region high reflection mirror coating is designed and calculated by using
plane-wave expansion method. Simple construction, combination of broad wave band beams in 2D and wide-angle is
realized, and polarization of off-axis incident beams is prevented. The analysis of infrared reflectivity and radio
frequency transmission rate demonstrates that this new method can perfectly satisfy the demand of design.

We analyze the nature of modal cutoff in photonic crystal fibers which core is filled with liquid crystal. The radius of
effective modal fields is used to determine the cutoff wavelength and fiber dimension between the regimes with
single-mode and multi-mode operations in the photonic liquid crystal fibers (PLCFs). After calculated the normalized
frequency V, we establish the parameter subspace in photonic liquid crystal fibers (PLCFs) are single mode.

We report a new configuration of logic gates based on single hexagonal-lattice PCRR composed of cylindrical silicon
rods in air. Two types of inner ring including regular hexagonal and circular are numerically discussed by using 2D
finite-difference time-domain (FDTD) technique. The impact of surrounding periods and scatterers like size and relative
phase at each input port was investigated. The logic '0' and '1' of hexagonal ring can be defined as less than 17% and
greater than 85%, respectively, much better than early reported square-lattice results. The simulation results also proved
that photonic logic gates based on this new single PCRR can really function as NOT and NOR gates, respectively.
These findings make PCRRs potential applications for all-optical logic circuits and ultra-compact high density photonic
integration.

Based on ultrahigh-order modes in symmetric metal-cladding waveguide with millimeter
scale, a new oscillating wave sensor is investigated to measure minute changes in various
parameters of aqueous solution. In the proposed geometry, the sample acts as the guiding layer
where oscillating waves propagate. Owing to the concentrated power in the sensing region and the
use of the very sensitive ultrahigh-order modes and the unusual large Goos-Hänchen shift, it is
demonstrated both theoretically and experimentally that its sensitivity is enhanced by one order of
magnitude than that of evanescent wave sensor.

We added excess silicon into erbium silicate to form silicon-rich erbium silicate (SRES) films on p-type silicon
substrates by magnetron sputtering technique. After annealed at 850°C in N2, the element contents of erbium, silicon and
oxygen in the films were estimated by Rutherford backscattering spectroscopy. Room temperature Er3+ 1.54 μm
electroluminescence from the structure of indium tin oxide (ITO)/SRES/p-Si has been studied. Its electroluminescence
intensity can be markedly enhanced by optimizing the excess Si content in the SRES film.

In this paper, an accurate Fourier Optics method of designing AWG demultiplexer based on high-index-contract
Silicon-on-Insulator (SOI) materials is presented. The typical SOI photonic wire waveguide has a cross section of
400×340nm2 satisfying single-mode condition, and operating central wavelength is 1.5500μm. A three-stigmatic-points
method is also applied in order to improve the accuracy, considering the aberration theory. Furthermore, our AWG has
another important characteristic--the flat field of the output ports. In the example presented here, we design a 1×256
channel AWG with 0.1-nm channel spacing. The simulation result shows that the insert loss is almost 0dB for the central
and peripheral output ports as well, representing a good uniformity. Meanwhile, the crosstalk to the adjacent channel is
14.4dB. Free spectral region (FSR) equals to 30nm as designed.

It is necessary to take some research into the thermal analysis of polymer waveguide ,which is important to
the interconnection among chips ,in order to guide the improvement of the technique of conventional integration and
make it more advanced. In this paper, we are successful in making a polysiloxane rib waveguide which is 21 cm long
like a line, and laser can propagate along the rib area directly. In order to take a research in the compatibility between
this waveguide and the integration technique, we analyze the thermal characteristics of the waveguide applying the
ansys software. We make the analysis model and meshing it. We also set the boundary conditions, and take some
research in the thermal characteristics of the waveguide and its thermal distribution of its cross section according to the
time. At last , we get that the instantaneous high temperature can not infect the core layer. We also get that the
temperature as high as 400 °C can not lasting more than 0.035 seconds. Those all conclusions are useful to the
integration technique.

A Faraday-Fabry-Perot (FFP) cavity, composed of an Fabry-Perot (FP) cavity and a piece of Faraday magneto-optical
material, is presented. The principle of FFP cavity and its polarization modulation effect are described by use of optical
matrix analysis. The result shows that the Faraday rotation is able to be magnified by more than two orders of magnitude
in resonant FFP cavity, while different elliptically polarized lights are obtained in non-resonant cavity. Furthermore two
novel applications, that is, optical isolator based on passive FFP cavity (FOI) and Faraday-Zeeman dual-frequency laser
(FZDL) based on active FFP cavity whose eigen modes operate as circularly polarized lights and whose frequency
difference can be adjusted continuously by magnetic field, are introduced. The principles, typical parameters and
performance characteristics are analyzed in both applications.

Tree-type network composed of optical splitters and optical combiners, according to
the corresponding link rule, plays an important role in the all-optical communication and optical
information processing. Based on the matured polarization control technology to realize routing
and switching of signal beams, a novel tree-type interconnection network using phase spatial light
modulator (PSLM), polarizing beam-splitter (PBS) and mirror, is proposed, including 1×2, 1×4,
and 2×1, 4×1 switch elements. It is able to perform any arbitrary interconnection pattern, which
has the advantages of compact in structure, efficient in performance, small size, and
polarization-independent due to exploiting the building block pattern. The theoretical analysis
shows the functional experimental prototype with large number of input/output ports should be
helpful in the optimization and design of large-scale optical switch matrix.

A plasmonic Bragg reflector with rectangular-shaped transmission spectrum based on MIM (Metal-Insulator-Metal)
waveguides is proposed and theoretically analyzed in this paper. As the MIM waveguide structure is treated as a cascade
structure of multi-F-P cavities and by use of Transfer Matrix Method (TMM), the property parameters of the reflector is
related to the structure parameters of grating, so that the performance index of reflector can be optimized. As an
example, a wide bandgap reflector is designed by this method, the center-wavelength of it at 1550nm, the full width at
half maximum (FWHM) of it at 640nm and the center-transmission of it approaching zero.

We proposed and demonstrated an all-fiber laser to generate cylindrical vector beams at
1030 nm. The cylindrical vector beams were obtained by exciting high order mode operating in
the few-mode fiber inside the laser system, which was implemented through adjusting the angle
and transversal dimension of a couple of fiber collimators. The radial and azimuthal polarization
beams can be switchable conveniently just by applying twist and pressure to the few-mode fiber.

We develop a simple iterative model to simulate a laser with homogeneous gain and intensity dependent loss. Simulation
results show that a laser with homogenous gain can operate at multiple wavelengths if the intensity-dependent loss
exhibits saturable transmitter characteristics. Our results also show that for nonlinear losses that have both saturable
transmitter and saturable absorber characteristics, such as arises from nonlinear optical loss mirrors (NOLM) or
nonlinear polarization rotation (NPR), the multiwavelength output power spectrum can become very flat. The laser can
also exhibit periodic and chaotic behaviors. We find that the same theoretical model can also be used to describe multipulsing
dynamics of mode-locked lasers when the cavity energy increases. Near the multi-pulsing transitions, both
periodic and chaotic behavior can be observed as operating states of the laser cavity. Our iterative model provides a
simple geometrical description of the entire multi-pulsing transition behavior as a function of increasing cavity energy.
The model captures all the key features observed in experiments, including the periodic and chaotic mode-locking
regions, and further provides valuable insight into laser cavity engineering for maximizing performance.

In this paper, we propose an ultrashort pulsed waveguide laser using carbon nanotube saturable absorber integrated
with gain medium, in which the carbon nanotube saturable absorber is directly sprayed on the Er-Yb doped phosphate
glass ion-exchange waveguide, a linear cavity is chosen. The waveguide structure and lasing performance of the
proposed waveguide laser are analyzed theoretically. The effects of the nonlinear coefficient and cavity dispersion on
the output characteristics of the ultrashort pulsed waveguide laser are discussed.

The variable separation method and coordinate transformation is presented for solving the
refractive index distribution of the regular hexagon GRIN lens. Through the software
programming, the exact solution of the refractive index distribution is proved by the correctness.
The result is obtained for the manufacture of imaging systems and characteristics. The model can
be extended to solve the even-numbered polygon edges in the positive refractive index distribution
of GRIN lens.

DFB Fiber laser based sensors, including strain sensing, temperature sensing and acoustic sensing, have attached a lot
interests because of high performance and small size.We demonstrate a simple DFB fiber laser hydrophone and its
demodulation is realized by a simple intensity based scheme. The reasons of the intensity modulation of DFB fiber laser,
including gain demodulation, feedback effect, and polarization demodulation, are discussed in detail based on rate
equations. The frequency response of the DFB fiber laser based hydrophone is measured in an anechoic water pool and
compared with a referenced B&K8104 hydrophone.

We have theoretically investigated the polarization properties of a single-mode photonic crystal fiber (PCF), which is
pulsed one-side by CO2 laser resulting in partial air-holes collapse and deformation. The CO2 laser micro-fabrication is a
common way in PCF post-processing, which is used widely both in writing fiber gratings on PCFs and making optical
components such as PCF polarizers. A series models with different valley depth which is due to the collapsed air-holes
have been simulated by using a full-vector finite-element method (FEM) with a perfectly matched layer (PML). The
theoretical results show that the deeper valley causes a larger insertion loss, at the same time, leading a larger
polarization dependence loss (PDL). This research provides an insight into the side-pulsed PCF as well as a guidance on
the experiment of CO2 laser micro-fabrication on PCFs.

We designed and experimentally reported modified potential InGaAs/InAlAs coupled quantum wells. In this structure, a large blue shift of the absorption edge of more than 35 meV is obtained at a reverse bias of -4 V. This predicts that a large negative electrorefractive index change can be achieved at longer wavelength region of the absorption edge.

We have studied the effect of buffer layers on the performance of poly(3-hexylthiophene-2,5-diy1) (P3HT):C61-butyric
acid methyl ester (PCBM) bulk heterojunction solar cells. We proved that depositing a thin pentacene layer between
metal cathode and P3HT: PCBM blend and introducing a thin P3HT layer between ITO and photoactive layer, would
improve the power conversion efficiency of polymer bulk heterojunction solar cells when compared with the cells
without the buffer layers. In the study, the buffer layers increased short circuit density (Jsc) and open circuit voltage
(Voc) under the illumination by white light from a solar simulator with an incident intensity of 100mW/cm2. The thin
pentacene layer as a cathode buffer layer modifying the contact between the active layer and the cathode, the thin layer
of P3HT as a anode buffer layer enhancing the electron blocking ability were responsible for the improvement on the
performance of photovoltaic device.

A electric field technique was developed to fabricate 1×4 buried channel waveguides on
optical glass. The 40V voltage was applied on the glass to accelerate the exchange of sodium ions
in the glass and cesium ions in the salt melt. As a result, the optical loss of 0.1dB/cm was obtained
for channel waveguides of 20μm depth with the 1.550μm laser, and a 3D buried channel
waveguide is produced by the non-uniform field ion exchange under 1μm height inclined on glass.

Quartz crystal is a good piezoelectric crystal and it can be used as substrate of surface acoustic wave (SAW) devices.
How to cut the substrate crystal is important in design of the SAW devices, and the optimum cut direction is determined
by the direction of the largest electromechanical coupling coefficient. In this paper, SAW basic equation group
strengthened by piezoelectric effect and boundary condition equation group including mechanical boundary conditions
and electric boundary conditions are deduced. The electric boundary conditions have two kinds: free boundary condition
and short-circuit boundary condition. Two kinds of SAW velocities using the two kinds of electric boundary conditions
are systematically calculated for the quartz crystal respectively in decoupling of yz plane. The SAW velocities are
calculated using a circle iterative method, which calculation velocity is quick and calculation precision is high.
Electromechanical coupling coefficient is calculated using these two SAW velocities in yz plane of the quartz crystal.
Calculation results indicate that the maximum electro-mechanical coupling coefficient is 0.2885 at direction, which
makes an angle of 73° with y axis, in yz plane of the quartz crystal. The calculation results lay a solid foundation for
design and manufacture of the SAW devices.

We proposed a new channel drop filter (CDF) based on race-track photonic crystal ring resonator (PCRR) composed of
square-lattice cylindrical silicon rods in air. Two representative scenarios, parallel and perpendicular, related to the
direction of race track and bus channel waveguide, are comparably studied by using 2D finite-difference time-domain
technique. A good set of parameters with adequate modal spacing can be determined by adjusting the amount and size
of scatterers. By optimizing the relationship among surrounding periods, race-track ring size and coupling strength,
more than 150 spectral quality factor and 93.9% dropped efficiency can be achieved at 1370-nm channel for one single
race-track PCRR. These findings enhance and enrich the PCRRs as an alternative to current micro-ring resonators for
ultra-compact WDM components and high density photonic integration.

The built-in electric fields formed in varied doped GaAs photocathode may promote the transport of electrons from the
bulk to the surface, thus the quantum efficiency of varied doped cathode can be enhanced remarkably. But the really
reason of this enhancement, which may be either the increase in the amounts of electrons reaching the surface, or the
increase in the energy of the electrons arriving at the surface, is not clear at present. In this paper, the electrons energy
distributions in varied doped photocathode and uniformed doped photocathode before and after the electrons escape
from the cathode surface were analyzed, and the amounts of the electrons escaped from the surface in different case
were calculated for the two kinds of photocathode. The analysis results according to the experimental result indicate
that, the varied doping structure may not only increase the amounts of the photoelectrons arriving at the surface, but
also cause an offset of the electrons energy distribution to high energy, and which is the root reason for the
enhancement of the quantum efficiency.

Transparent thin films are manufactured by PLD (pulsed laser deposition) in different oxygen pressure. The various
property of samples is measured by Atomic Force Microscope (AFM), X-ray diffraction (XRD) and optical transmission
spectrum. All samples retain the original structure in wurtzite lattice by XRD, there is not being of metallic cobalt or
other impurity phase with the limit detection. The surface morphology of the films observes the smoother than that in
undoped ZnO thin film. The transparency of thin films has altered greatly with the different oxygen pressure or not by
PLD, which is shown that the oxygen pressure has impacted on the transparency of the film and surface morphology.
And UV-visible spectra fully have been demonstrated the presence of Co2+ to substitute for Zn2+ in the films with the
different oxygen pressure.

A broadband waveguide amplifier based on long-period waveguide grating and multilayer medium thin film filter is
proposed. The long-period waveguide grating is directly written in the Er-Yb codoped phosphate glass waveguide by
using UV-written technology and the multilayer medium thin film is coated on the output interface of the waveguide.
The light transmission characteristics of the proposed filter are analyzed theoretically. The effects of the transmission
spectra of the filter on the flattening gain spectrum of Er-Yb codoped phosphate glass waveguide amplifier are
discussed. It's demonstrated that the flatness of below 1dB is achieved over a bandwidth of ~ 30nm.

We proposed a novel optical fiber hydrophone based on the feedback effect of a composite cavity optical fiber laser
(CCFL) and a corresponding intensity demodulation scheme. The feedback of the CCFL is introduced by the end face
reflection of the single mode optical fiber. The intensity modulation of the CCFL is caused by the modulation of the
CCFL feedback.

The Eu(DBM)3phen-doped polymer optical fiber slice was prepared, and the population of Eu3+ ion was up to 1.0
wt.-%. The chromatic dispersion and absorption characteristics of fractal clusters of Eu3+ ions in Eu(DBM)3phen-doped POF slice were explored. The dielectric components homogeneously and inhomogeneously doped circumstances of this
kind of POF slices were studied and their transmissions were analyzed and compared theoretically. Using near-field
scanning optical microscopy (NSOM), the near-field light intensities of this kind of POF slice were measured, and agreement was obtain between experiment and theory. The result indicates that the clustering in this kind of POF is not
obvious.

For the long wavelength infrared detection, HgCdTe (MCT) photoconductive devices are selected as the core of
next-generation meteorological because of its mature fabrication technique and stable performance. During the assembly
process, an innovative multilayer ceramic board providing mechanical support is designed as the electrical
interconnection between MCT chips and external circuits for cryogenic application. Furthermore, due to its brittleness,
long linear MCT device is normally glued to sapphire substrates on the multilayer ceramic board with cryogenic glue.
Thus, it can be seen clearly that the assembly structure is a multilayer configuration which comprises various kinds of
materials, including ceramic broad, sapphire, MCT and glues. As a result, the difference in Thermal Expansion
Coefficient (TEC) between the layers could create the potential to introduce thermal stress at working environmental
temperature (approximately 70K), which could result in device performance degradation, even die crack.
This article analyzes the thermal stress between long linear MCT devices and a multilayer ceramic board by using Finite
Element Method (FEM). According to analysis results, two factors are revealed as the most significant causes for
introducing thermal stress: one is the sapphire substrate thickness; the other is the parameters of various materials, for
instance Yong's modulus and TEC. Since the structure of MCT detector is determined by system requirements and is
under the limitation of manufacture technology, this article reveals two effective approaches to reduce the unavoidable
thermal stress: first, choosing the appropriate thickness of ceramic board which is made by Al2O3; second, adding another
metal cushion Invar. With the above considerations, the distribution of thermal stress is simulated using FEM under
different parameter conditions. Based on the results of simulations, an optimal design of package structure which could
improve the reliability of linear MCT with minimum thermal stress is demonstrated.

The far-field distribution of single-mode fiber is studied; the Gaussian approximation for it is analyzed based on the
characteristic of beam propagation factor and then its rationality is explained. Through researching the matching
efficiency between the far-field and Gaussian field, a new definition of divergence half-angle is presented according to
the maximal matching efficiency method; furthermore, a formula of the maximal matching efficiency divergence halfangle
as function of normalized frequency is given.

Uncooled focal plane array (UFPA) has broad application prospects in civilian and space because it's cheaper, more
compact and high reliability. Many research institutes and companies have carried out the research of uncooled focal
plane array. This paper shows a vacuum package design of UFPA, and its architecture will be given. The assembly is an
all-metal vacuum package, which has been proven rugged and reliable. Out-gassing, permeation, evaporator, and air leak
are factors to reduce the component vacuum lifetime. Theoretical analysis shows that material out-gassing is the main
factor of pressure rise inside package. Theoretical analysis and calculation show that designed metallic structure can
meet the need of 10-years life.

In this paper, numerical simulation and analysis of the sensitivity of Strength-based Optical Fiber Sensors (SOFS) have
been reported .The results simulated show that suitable operating point can improve sensitivity of the sensing system
greatly even up to 3.6%. This conclusion can provide theoretical support for optimizing actual strength-based optical
fiber sensors with higher sensitivity.

The electro-holographic optical switch based on the quadratic electro-optic effect in paraelectric photorefractive crystals
requires driving signal of fast pulse. The pulse rise/fall time and voltage are 10-10-10-8s and 102-103V, respectively,
depending on the applications. A pulse control signal generator for the electro-holographic optical switch was designed
and simulated. Considering the integration of pulse signal generator and the switch, the circuit employs three stages
compact Marx generators utilizing parallel avalanche bipolar junction transistors series operated in the avalanche mode
in each stage. These transistors and the crystals are mounted on printed circuit board. According to the simulated results,
the output voltage ranged from 1.2kV to 1.5kV. The rise/fall time of this pulse is less than 3 nanoseconds. The pulse
width is 20 nanoseconds, and trigger delay is about 1 nanosecond. The repetition rate is less than 50MHz which can be
increased by reducing the pulse width of the trigger. The simulation results indicate that the pulse control signals from
the designed generator can match the application of electro-holographic optical switch well.

This paper presents an improvement approach to realize tracking on smooth glass surface based on
subjective speckle. The scattering mechanism on glass surface is analyzed and the affection on tracking
precise and range for tracking with subjective speckle is researched. The speckle captured by CCD just
from the upper surface of the glass is achieved by grazing incidence of the laser beam and the noise
mixed with the signal is eliminated by a barrier above the surface. Based on the apparatus of subjective
speckle tracking, the speckle contrast is improved from 0.25 to 1.25 by non-Gauss effect and the range
of the tracking has been increased from 200 μm to 400 μm compared with the objective speckle
method on the same condition.